It is known that the kidney is an important organ which has a function of maintaining the composition of body fluids normally by controlling excretion of water and salts in the body fluids, and that when the renal function is disturbed, it results in a decrease in renal blood flow and thereby a decrease in excretion of salts, particularly sodium (cf. "Rinsho Yakurigaku Taikei" (Test for Clinical Pharmacology), Vol. 8, Diuretics Transfusion, pages 54-55, issued by Yamanaka Shoten, 1966).
In order to remedy the kidney deseases, it is useful to use a medicament having increasing effects on the renal blood flow and also on the excretion of sodium.